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Mary's Room is a poor argument for Dualism.

2023-07-24T00:00:00+00:00

Mary's Room is a poor argument for Dualism.

Mary is a brilliant scientist who is, for whatever reason, forced to investigate the world from a black and white room via a black and white television monitor. She specialises in the neurophysiology of vision and acquires, let us suppose, all the physical information there is to obtain about what goes on when we see ripe tomatoes, or the sky, and use terms like ‘red’,’ ‘blue’, and so on. She discovers, for example, just which wave-length combinations from the sky stimulate the retina, and exactly how this produces via then central nervous system the contraction of the vocal chords and expulsion of air from the lungs that results in the uttering of the sentence ‘The sky is blue’. [..] What will happen when Mary is released from he black and white room or is given a colour television monitor? Will she learn anything or not? It seems just obvious that she will lean something about the world and our visual experience of it. But then it is inescapable that her previous knowledge was incomplete. But she had all the physical information. Ergo there is more to have than that, and Physicalism is false.

…So goes the famous Mary’s Room thought experiment. This is an argument, formulated by philosopher Frank Jackson intended to disprove the doctrine of Physicalism.((Physicalism is the idea that everything that exists is physical. This is a rather vague statement. If it helps physicalism, in practice, is usually used as a synonym for materialism and for the purposes of the Mary’s Room thought experiment, that’s probably good enough. However, there is a slight difference between materialism and physicalism. Historically, materialism is associated with the beliefs of the ancient Greek Atomists such as Democrites and Epicurus. The ancient Greeks, and the early modern philosophers who were influenced by them, attempted explain reality in terms of the motions of microscopic particles called “atoms” this is before the modern discovery of atoms by modern physics, and the motion and interaction of these atoms. The ancient atomists didn’t believe in things like gravity or other physical forces, and consequently, classical understandings of materialism don’t account for those sorts of things. Modern physics is therefor incompatible with materialism as classically conceived, but physicalism doesn’t have that problem. Physicalism reduces things to physics even if physics itself isn’t reducible to matter.))((https://plato.stanford.edu/entries/physicalism/#Term)) One of the most famous and thorny topics in the history of the philosophy of mind is the subject of dualism. That is, are human beings simply physical beings or is the mind at least partly non-physical. In other words, do people have souls or are we just brains subject to the limitations of the physical world. Dualism, attributed to thinkers as diverse as Plato and Renee Descartes, is the doctrine that the mind is non-physical, that there is a duality between the body and the mind. Its opposite, would be physicalism, the doctrine that everything that exists, including the mind, is physical, and can ultimately be reduced to physics. This later stance is by far the more popular stance in the modern day.

Arguments for physicalism regarding the mind usually rest on the intuition that the mind and its operations seem to at last be partly synonymous with the brain which is clearly a physical organ. Physicalists tend to look at the success of modern science and its ability to explain formerly inexplicable things in terms of physical laws and intuit that physical laws can probably also explain things that we don’t yet have a full satisfactory explanation of, such as the mind. However, there are still modern day dualists, many of whom believe that there is something ineffable in human consciousness that just can’t be captured with a physicalist explanation. One popular appeal that such philosophers make is to qualia, the details of subjective conscious experience and how, intuitively, according to them, it doesn’t make sense that qualia can exist in purely physical terms.

One such philosopher was Frank Jackson, a self described “qualia freak”, who believed that qualia could be used as part of an argument to refute physicalism. His paper, Epiphenomenal Qualia was an attempt to make such an argument and one of the central parts of that paper was the Mary’s Room thought experiment cited above. Mary’s Room has proved to be a very popular argument for modern dualists, in part because it’s easy to understand, but I don’t think that it is a very good one.

The Argument from Qualia

At its heart, Mary’s Room is an argument that there are more kinds of knowledge than just physical knowledge. When Jackson originally wrote his paper, he took physicalism to be the stance that, “the thesis of Physicalism” is “that all (correct) information is physical information.” But Jackson disagree with this stance. He believed that there was another kind of information, the kind of information that one got from direct sense experience that was not expressible in terms of mere physics. As he put it:

Tell me everything physical there is to tell about what is going on in a living brain, the kinds of states, their functional roles, their relation to what goes on at other times and in other brains, and s an and so forth, and be I as clever as can be in fitting it all together, you won’t have told be about the hurtfulness of pains, the itchiness of itches, pangs of jealousy, or about the characteristic experience of tasting a lemon, smelling a rose, hearing a load noise or seeing the sky.

If nothing else, Jackson’s point of view here is quite poetic, so it’s easy to see its appeal. There is something ineffable about the experience of tasting a lemon that just can’t be expressed in a purely physical description of the process. These things that Jackson talks about, whether it is the hurtfulness of pains or the itchiness of itches are qualia, subjective conscious experiences, and the existence of these qualia, he argues, demonstrate that not every kind of knowledge is about something physical.

Think about Mary, who we described above. For whatever reason, while she has been allowed to learn everything there is to know about color vision, she has never been allowed to actually experience color vision and so she lacks a certain kind of knowledge, the knowledge of what it is like see color. Another philosopher, John Locke (a dualist) once noted:

Suppose a child had the use of his eyes till he knows and distinguishes colours; but then cataracts shut the windows, and he is forty or fifty years perfectly in the dark; and in that time perfectly loses all memory of the ideas of colours he once had. This was the case of a blind man I once talked with, who lost his sight by the small-pox when he was a child, and had no more notion of colours than one born blind. I ask whether any one can say this man had then any ideas of colours in his mind, any more than one born blind? And I think nobody will say that either of them had in his mind any ideas of colours at all. His cataracts are couched, and then he has the ideas (which he remembers not) of colours, DE NOVO, by his restored sight, conveyed to his mind, and that without any consciousness of a former acquaintance. And these now he can revive and call to mind in the dark.

In other words, the idea of color is something that must be experienced; it cannot simply be described. No physical description, it would seem, no matter how complete, replicates that experience. And that experience is itself a kind of knowledge.

Response

There are a number of different kinds of response to Jackson’s argument. Some of them hinge on the idea that with enough information maybe Mary could understand what it was like to see color even if she had never done it before, but I think the most compelling counterargument is to point out that Jackson’s argument is not actually against physicalism at all. Recall Jackson’s definition: Physicalism is the thesis “that all (correct) information is physical information.” This isn’t actually what physicalists believe. What physicalists believe is that everything that exists is physical, which is a different proposition altogether.

Let’s say that Mary does learn something when she is first exposed to color. Before she experienced color for the first time she was given all of the information possible about the physics of color and about the physics of the brain which result in the experience of color, but had never experienced color herself. Upon experiencing color for the first time she now knows what it’s like to experience color. This later knowledge is not knowledge about the physics of something, but the knowledge itself is nevertheless physical.

What do I mean by that? Well, if we accept for the sake of argument the physicalist position that everything in the mind including knowledge and experience reduces to different brain-states or groups of brain-states, then Mary’s experience of color, at least the way it expresses itself in her mind, is nothing other that a particular brain-state which is physical. In other words, her experience is a physical thing that happens, regardless of whether her knowledge is of physics per-se.

Let’s take another way of looking at this for a second. Let’s say you wanted to learn how to hit a baseball, You could try reading up on the physics of hitting a baseball, learning about how gravity and the wind resistance work on the ball as it travels through the air, about the mechanics of the body as you swing the bat, about what the proper form is and why it makes it possible to hit the ball, etc but all the reading in the world by itself will not let you hit a baseball on the first try. The moment you get up from your reading and actually try to hit a ball, you will probably miss. However, after practicing hitting a ball, and after swinging the bat many, many times at any, many balls, you will probably improve to the point where you can actually start hitting balls with some regularity. The reason is that there is a difference in knowing about something and experience in doing the thing.

What happens when you practice hitting a baseball? Well, like, a lot. Your muscles, nerves, and brain work together to develop a profile of what it feels like to swing the bat correctly and hit a baseball. Each particular position of the body, and each transition between those stances has a particular feel. In addition, the motions that the body must go through in order swing a bat require a coordinated motion of the muscles that must be coordinated with continuously updating information about the location and motion of the ball. When you practice hitting a baseball, the brain learns these feelings, motions, etc and connects them together in the locomotor portion of the brain. The nerves, muscles, and brain, all change so that the particular task of hitting a baseball can be done without engaging the higher portions of the brain. Much of the process automatic, as far as the practitioner is concerned. This is very different from what happens when you simply read about how hitting a ball works. Different parts of the brain are engaged when you learn about something than when you actually do something. Both of these things can be called “knowledge” but they are different things being given the same name; they are different types of “knowledge.”

This ultimately is the distinction that is being made in the Mary’s Room thought experiment. The term “knowledge” is being used to refer indiscriminately to brain-states but isn’t capturing the distinction between higher-order “book” knowledge which captures the relationships between idea and lower order experiential knowledge which relates different sense experiences together generating what we call “qualia” and which also helps to relate those qualia to the higher-order ideas. When Mary studies physics, she expands her “book” knowledge, but when she steps into the world and sees color for the first time, she expands her experiential knowledge. In neither case is it necessary that something non-physical is happening.

Higher-order ideas, so called “book” knowledge can be about physical things. It can also be about physics per-se. It can be about non-physical things, or about things that don’t exist. But none of that has anything to do with whether the knowledge itself is something physical; whether it is simply a brain state or there is something extra-physical going on. Something similar is true with experiential knowledge; whether the subject matter of knowledge is something physical is a different question from whether the knowledge itself is physical. Experience can be a physical process even if it can’t simply be derived from a sufficient understanding of physics.

Conclusion

So that’s the famous Mary’s Room argument and my preferred response. There are actually a lot of other responses to this argument, the majority of modern philosophers are physicalists. Even Frank Jackson has since abandoned epiphenomenalist stance he was arguing for when he first advanced his thought experiment. This might be surprising because physicalism vs dualism is a big debate in western philosophy and the most famous philosophers have historically been on the dualist side of the debate. That changed over the past century or two with the decline of the influence of Christianity and the rise of more secular schools of philosophy. Mary’s Room and the argument from qualia was a bit of a rearguard action by Jackson and other surviving dualists, defending a philosophical stance that has been losing ground for quite a while now.

Last update: 18/10/2023

Universals and the Game of Life

2023-01-01T00:00:00+00:00

Universals and the Game of Life

The Problem of Universals

In this world we are surrounded by particular things. A table, a chair, a house, a person… these are all individual particular things. But, many of the particular things around us have something in common. An apple is red and so might be a fire hydrant. A horse is fast and so is a race car. Napoleon was a person and so was his wife. Philosophers often use the term universals to describe these things that different particular objects have in common, or in other words, any word that can be predicated, or said, of multiple things is a universal. That means just about anything, “Horse” in a universal, because it refers to a category of things called “horses”. “Human” is a universal because it refers to a category of things called “humans”. “Redness” is a universal because it’s possible for more than one thing to be the color red. “Large”, “short”, “white”, “table”, etc… just about any adjective or noun that isn’t a proper noun is arguably a universal.

So, why do we care? Why invent a term like universal when we already have words like “noun” and “adjective”? Well, the answer is because there is an old and long-standing debate in philosophy as to the status of universals. Are universals “real”? That is, do things like, “orangeness” or “humanness” independent of particular orange things, or particular humans? Some ancient philosophers such as hugely influential Plato, would have emphatically argued “yes”.

Plato famously postulated the World of Forms, a separate world of pure forms upon which everything in our real, sensible, world is based. Forms in Plato’s jargon, is just another word for what we are here calling universals. At first blush, this idea seems a bit odd: why would someone feel the need to believe that everything in the world is based on things in this separate world of pure forms? The idea seems a bit unnecessary. However, there is a logic to the idea. Imagine, for the sake of argument, a geometrical figure, say a triangle. There are many things in the world that we can say are roughly triangular: pyramids, certain road signs, Piccadilly Circus, etc. Almost nothing in the world, however, can be said to be a perfect triangle. Rather, things in the real world sometimes approximate a triangular shape, so triangles as such don’t necessarily exist in the individual triangle shaped things in the world. Yet, we can still reason about perfect triangles and know, for example, that all (Euclidean) triangles have three corners whose angles sum up to 180°. If we can reason about triangles separately from individual triangle shaped things, it stands to reason, so Plato surmised, that “triangleness” is something separate from those individual triangle shaped things, and must have its own separate existence. Plato’s approach to universals is called metaphysical realism; he believed that universals are real in the sense that they have their own separate existence from the particular objects things that we experience in the real world.

Other philosophers, such as Aristotle, take a bit more moderate approach to metaphysical realism. For Aristotle, there was no world of forms, rather, for him forms existed in the particular objects which were instances of different forms. So, for example, a horse was said to be an instance of the form of horseness, and the form of horseness was present in each individual horse. For Aristotle, what made a horse, was that it instantiated the form of horseness. For Aristotle, forms could also exist in the minds of people who comprehended those objects. So, if you saw a horse or two and developed an idea of what a horse was, that idea was the form of horseness now existing in your mind. For Aristotle, the reason that we can know things that our minds are capable of intuitively grasping the forms of things we witness in the world in our heads and then reasoning about them. If forms didn’t exist, we wouldn’t be able to reason.

For many metaphysical realists, that last point is key. The reason they embrace metaphysical realism is that they maintain that reasoning and communication are impossible if the concepts that we reason about are not in some sense real. If “redness” for example, is not some real property of different things in the world, then we can’t meaningfully use the word “red” to describe things. And, for metaphysical realists, if redness is not some immaterial form, distinct from the red things themselves, it can’t be a real property, predicable of different things in reality.

Nominalism

Now, metaphysical realism has not gone unchallenged in philosophy. There have been many philosophers over the centuries who have taken issue with the notion that immaterial forms must be things that exist in order for human beings to be able to reason or communicate. Perhaps the most famous challenge to metaphysical realism was that of nominalism in the late Middle Ages, the notion that universals as such don’t exist and that words in general are just names that we apply to groups of particular things for convenience. The most famous of the early nominalists was a late medieval scholastic philosopher who we call William of Ockham. Ockham was Franciscan friar originally from southern England famous for, among other things, his advocacy for the principle of simplicity((This is sometimes called “Ockham’s Razor” after him. Ockham himself, however, never used the word “razor” to describe the principle of simplicity.)) as well as for his support of nominalist metaphysics.

Ockham embraced nominalism because he thought that metaphysical realism was self-contradictory. For Ockham, realism implies that a universal is both many things and a singular thing at the same time and that this was a contradiction. He argued that if a universal existed in the particular things that instantiate it, then destroying any particular would destroy the universal it instantiated. Destroying a horse for example, would destroy the universal “horseness” that every single horse in existence participated in. If that were not the case, then either “horseness” was not a single thing, or else it was not shared universally among all horses and in either case it would not be what philosophers call a universal.

So for Ockham, universals couldn’t be the thing particular objects held in common that let us talk about them. Instead, he argued for form of nominalism called conceptualism. He argued that we form concepts inside the mind, that correspond to groups of particular objects that we experience in the world. For example, a person might encounter a number of animals that have long legs and which people ride upon. In seeing that they are all pretty similar, they might develop a concept in his mind for this sort of animal and the name “horse” could then be applied to that concept. This concept is something that exists only in the mind, and it functions to link together multiple related experiences. In this schema, words such as “redness” or “triangularity” are not metaphysical realities that exist independent of the mind which are then revealed to the mind via some metaphysical or spiritual mechanism, but rather are constructs built by the mind to unify similar experiences.

The Debate

Nominalism vs Metaphysical Realism might seem like a bit of an esoteric debate, but it was actually quite a heated subject in the late Middle Ages and in the Early Modern Period. In fact, philosophers still debate the merits of either position. At the root of the debate is a concern about the objectivity vs subjectivity of language, logic, belief, even ethics and morals. Realist philosophers might argue that if “redness” for example were only a concept in the mind rather than a real property of things in reality, then the fact each individual might have his own private concept of “redness” might preclude any communication about redness or red things, because if we don’t have the same concept of redness then we can’t be certain that we are talking about the same thing.

A Nominalist might object to that argument, by pointing out that “redness” is only a sensation that occurs when light of a certain wavelength hits the eyes and not a property of objects properly. The sensation of redness might be produced in multiple ways, so there isn’t a single universal property of objects that constitutes “redness”. And besides, different people do have different perceptions of color, such as people who are red-green colorblind and can’t distinguish “redness” from “greenness” and people from other cultures who sometimes distinguish colors differently. A nominalist might continue to point out that popular debates such as “Is a hotdog a sandwich,” imply that different people often have different ideas about the correct definition of a given word, that is, they have different concepts that they use the same word for, and yet still manage to meaningfully communicate with those words most of the time. This would imply that at least some universals, such as “sandwich” are nominalist rather than realist in nature and that this has not caused the breakdown in communication that metaphysical realists suggest would happen. We may not all have the same concept of a sandwich, but we can order them in restaurants just fine. As the philosopher Karl Popper pointed out while defending nominalism:

A term like “sand dune” or “wind” is certainly very vague. How many inches high must a little sand hill be in order to be called “sand dune”? How quickly must the air move in order to be called “wind”? However, for many of the geologists’ purposes, these terms are quite sufficiently precise, and for other purposes, when a higher degree of differentiation is needed, he could always say, “dunes between 4 and 30 feet high”, or “wind of a velocity between 20 and 40 mile an hour”. And the position in the more exact sciences is analogous. In physical measurements, for instance, we always take care to consider the range within which there may be an error; and precision does not consist in trying to reduce this range to nothing, or in pretending that there is no such range, but rather in its explicit recognition.((K. Popper - The Open Society and its Enemies))

A realist might not be satisfied with this rebuttal, arguing even if a nominalist approach can provide a satisfactory solution to some universals, it still doesn’t apply to all. For example, a (Euclidean) triangle always has angles that sum up to 180°. We can deduce this without dealing with any triangular object in particular, merely by considering the logical consequences of “triangularity”. From that it would seem that “triangularity” is something more than just a name used for objects that bear a certain similarity to each other and instead represents some kind of metaphysical reality, otherwise we wouldn’t be able to reason in abstraction from particular things.

Now, there are different kinds of nominalist and different kinds of metaphysical realist and different philosophers have different takes as to what universals can be treated nominally and which kinds must be real. Some philosophers treat mathematical concepts as real and others don’t. I think that it’s possible to defend a nominalist interpretation of mathematics through reductionism.

The Game of Life

In 1970 a mathematician name John Conway devised a single player game he called the Game of Life. This was a cellular automaton model, a form of simulation in which a grid of “cells” cycle through different states based on the values of their neighbor cells. These cellular automata models were invented to demonstrate a reductionist model of self-replication, that is with a certain rule-set and initial condition, a certain pattern of cells could be made to replicate itself indefinitely. Different cellular automata followed different rules and had different behavior, but Conway’s Game of Life managed to be a particularly interesting variation based on a rather simple set of rules. In the Game of Life, cells are either “alive” or “dead” and between each generation the state of the cells would change according to the rules as follows:

Any live cell with fewer than two live neighbours dies, as if by underpopulation.
Any live cell with two or three live neighbours lives on to the next generation.
Any live cell with more than three live neighbours dies, as if by overpopulation.
Any dead cell with exactly three live neighbours becomes a live cell, as if by reproduction.

The result was a surprisingly complex system with surprisingly complex attributes. One interesting attribute of the Game of Life is that there are many different patterns that appear in the game. Some patterns appear naturally and frequently whereas others are uncommon or need to be created intentionally. Patterns have predictable and sometime complex behavior. Some common patterns are very simple and have very simple behavior, such as the “block” pattern which doesn’t change from one generation or another or the “beacon” pattern which appears to blink on and off. Some are a bit more complex, such as the “glider” which moves continuously in one direction. In fact the behavior of patterns can be made arbitrarily complex, with entire computers being simulated in a single game of life.

Many of the patterns in the Game of Life are recognizable and appear frequently. We have names for many patterns, including all the most common ones. Yet these patterns, even the most complex ones, are all reducible to a simple set of rules as listed above. There isn’t any such entity as a “glider” built into the rules of Life, but they nevertheless appear spontaneously as a result of many other patterns. In that sense, a nominalist account of these patterns makes more sense than a metaphysical realist account. “Glider” is a name that we apply to a common pattern that appears similar to instances of a glider. The common behavior is caused, not by a common metaphysical “gliderness” shared by all gliders, but by the rules listed above. “Gliders” rather, are an emergent property of the Game of Life; we simply invent the name “glider” to refer to them.

It’s worth pointing out that most of the patterns that result in the Game of Life were not intentional and were not designed into the system. Conway did not know what patterns would emerge when he settled on the rules listed above. Instead, they are the consequences of the system as such, not of any particular design on the part of the systems maker.

We can analogously argue, that in the physical world, geometric and other mathematical constructs such as triangles are themselves emergent properties of a physical world ruled by a set of rules, including rules governing how matter is arranged in a three-dimensional space. It was not necessary that triangles have the properties that we associate with them. There are non-euclidean forms of geometry in which the angles of a triangle don’t add up to 180°. And there are certain mathematical spaces, in which triangle inequality does not hold. By this conception, a triangle, like a glider or beacon in the Game of Life, is an emergent property of space. Triangles are possible because space is shaped in a certain way, and triangles appear in nature because various natural processes result in them. That triangles seem to have common properties is due not to a universal “triangularity” that all triangles have in common, but to the fact that triangles are a result of the way space is shaped. The shape of space is what triangles have in common, and we can reason about triangles because we can reason about objects in space.

A die-hard metaphysical realist might insist that the shape of space can instead constitute a universal and have other universals be reducible to that common base universal. However, traditional nominalists such as Ockham didn’t object to the idea of objects existing in a common space or being subject to common rules; they objected to concepts like “horse” having a distinct reality independent of the objects we call “horses”. A situation where horses are reducible to physical laws still allows for a nominalist approach to horses. We have an understanding of what horses are because we experience them individually in reality, not because we directly perceive the fundamental laws of nature and how they can result in horses. So for any practical purpose, horses are understood in a nominalist fashion, as a word for a group of things that exist in nature that seem similar, rather than in the realist manner of directly perceiving the essence of horseness whenever we encounter a horse.

Conclusion

The interesting thing about this approach is that it flips the whole debate on its head. Traditional scholastic philosophy conceptualizes the physical world as matter shaped by forms, these forms essentially being universal essences and our ability to engage with and understand the world around us is because of the structure provided by those forms. A more contemporary understanding instead conceptualizes the physical world as composed of matter which follows a fixed set of rules. In this way, consistency and the resulting intelligibility result from the fact that objects are part of the world which is intelligible rather than the world being intelligible because it is populated by intelligible objects. The world is intelligible because of the consistency of the rules which govern it, a presupposition we call uniformitarianism. That is the beginning of modern science.

Last update: 19/01/2023

Civilizations are complex systems

2016-03-29T00:00:00+00:00

Civilizations are complex systems

There is an interesting paper called How Complex Systems Fail. It’s a collection of 18 related observations about complex systems and about when and how they fail. The observations are as follows:

Complex systems are intrinsically hazardous systems.
Complex systems are heavily and successfully defended against failure.
Catastrophe requires multiple failures – single point failures are not enough.
Complex systems contain changing mixtures of failures latent within them.
Complex systems run in degraded mode.
Catastrophe is always just around the corner.
Post - accident attribution accident to a ‘root cause’ is fundamentally wrong.
Hindsight biases post - accident assessments of human performance.
Human operators have dual roles: as producers & as defenders against failure.
All practitioner actions are gambles.
Actions at the sharp end resolve all ambiguity.
Human practitioners are the adaptable element of complex systems.
Human expertise in complex systems is constantly changing.
Change introduces new forms of failure.
Views of ‘cause’ limit the effectiveness of defenses against future events.
Safety is a characteristic of systems and not of their components.
People continuously create safety.
Failure free operations require experience with failure.

It’s worth reading the paper in it’s entirety but the gist of the paper is that attempts to analyze failures in complex systems are often themselves doomed to failure because of false assumptions about the nature of these systems. The main point is that because complex systems are inherently redundant, attempts to reduce collapse to a single point of failure are incorrect. In fact multiple failures have to occur simultaneously for the system to fail completely and furthermore, complex systems tend to contain multiple failures at any one time anyway. It’s the confluence of just the right combination of failures that causes the entire system to collapse.

Ultimately, a holistic approach must be taken to the health of the system.

Interestingly, complex systems in the sense meant by this paper tend to be systems with human components. Hospitals, stock markets, firms, and metros would be examples of complex systems. It’s not mentioned in the paper, but I suspect that if these human institutions constitute complex systems, wouldn’t bigger human institutions such as governments and entire civilizations constitute the same? If so, and I think this is the case, then this analysis would apply to these bigger things as well. Attempting to figure the cause of the collapse of civilizations such as the Roman Empire or the Maya would run into the same roadblocks as analyisis of those other sorts of systems. You would not be able to pinpoint the cause of collapse to any one factor or reason.

Perhaps the most famous history book of all time is Gibbon’s The Decline and Fall of the Roman Empire. This is a long and comprehensive account of Rome from its supposed peak in the second century to the final collapse of the Byzantine Empire. One of the most interesting things about this book is that Gibbon attempts to forward a thesis about why the empire ultimately collapsed. He believes that the decline of civic and martial virtue over time, hastened by the rise of Christianity, lead to Rome’s eventual inability to defend itself from the Barbarian invaders, which is a quite straightforward explanation.

However if the complex systems theory of civilizations is true, it would suggest that Gibbon’s explanation for the fall of Rome is far too simple and that many other factors likely contributed. And in fact, it looks like that might be the case. Many historians have taken Gibbon’s account to task and his explanation is no longer very popular, but the number of explanations proffered in its place are numerous. In fact, there are at least 210 given reasons for the Fall of Rome, and this kind of figures. Why should there be a simple, straightforward explanation? Rome as a civilization transformed itself almost entirely multiple times of the course of millennia, yet continued to run up until the very end. When one strength would disappear it would compensate with another. It would take a long series of disasters to finally destroy the empire.

Likewise, when people talk of lost civilizations such as the Maya or the Indus Valley Civilization, and wonder what happened to the them, perhaps there isn’t a simple satisfying answer such as ‘war’ or ‘famine’ or ‘a decline in civic virtue’. Perhaps the real answers is the much less satisfying ‘many things ultimately came together over hundreds of years to force the collapse of the civilization’ and perhaps the attempt to draw a simple lesson from these collapsed civilizations is an exercise in vanity? When a confluence of many factors leads to such a dramatic collapse it’s easy to pick out the ones we want and to use them to construct an easy moral which conforms to our preconceived notions. And so maybe the thing we learn about when we study civilizational collapses is really ourselves.

Last update: 20/05/2016

Using a Parallax 28340 RFID reader on the Raspberry Pi

2016-01-09T00:00:00+00:00

Using a Parallax 28340 RFID reader on the Raspberry Pi

Recently, a fried told me he was having trouble getting a Parallax RFID reader working on a Raspberry Pi for a project he was working on. I wondered how hard it could be so I got one of the readers for myself and hooked it up to a Pi. It turns out that it was harder than I thought it would be, but only because I didn’t know what I was doing.

When the reader is connected to the computer, it is auto-mounted as a serial port at /dev/ttyUSB0. You might think that because the letters ‘tty’ are in the device name that this is a TTY device, but it turns out that TTY devices are just connected over serial ports. This was not actually a TTY device. Once I understood that, it turns out that connected to a serial port on Linux though Python is actually rather simple. One just needs the pyserial library.

Here are some instructions and sample code to get this device working with a Raspberry Pi:

First install pyserial:

sudo pip install pyserial

Then you can connect to port by putting this in your python code:

import serial
port = serial.Serial('dev/ttyUSB0', 2400, timeout=1)

You’ll either need to run your script with root level permissions (IE, with sudo), or change the ownership of the device before running the script.

The full script bellow, will save each tag id read to a sqlite database on the Raspberry Pi. Each time it does so, It will blink the light on the reader. To read the database, you’ll want to install the sqlite3 client program:

sudo apt-get install sqlite3

Here’s the full sample program:

#! /usr/bin/python

# To use this code on the Raspberry PI, you'll need to install the pyserial module.
# You'll also want to install the sqlite3 package. To install these run these commands
# from the terminal on the Raspberry PI:
#
#  sudo pip install pyserial
#  sudo apt-get install sqlite3
#
# If you have trouble installing sqlite, try first running:
#
#  sudo apt-get update; sudo apt-get upgrade
#

import serial
import time
import sqlite3

# open sqlite database file
db = sqlite3.connect('tagreads.db')
cursor = db.cursor()

# check that the correct tables exists in database; create them if they do not
tables = cursor.execute("SELECT name FROM sqlite_master WHERE type='table' AND (name='tagreads');").fetchall()
if len(tables) == 0 :
  cursor.execute("CREATE table tagreads (timestamp, tagid)")

# connect to serial port on which the RFID reader is attached
port = serial.Serial('/dev/ttyUSB0', 2400, timeout=1)

lastid = ""

try:
  while True:
    # attempt to read in a tag
    tagid = port.read(12)

    # if tag read success full, save it to database and wait half a second;
    # else try again
    if(len(tagid) != 0) and (len(lastid) == 0):
      # close and open the port to blink the light and give visual feedback
      port.close()

      tagid = tagid.strip()
      timestamp = time.time()
      cursor.execute("INSERT INTO tagreads VALUES (?,?);", (timestamp, tagid))
      db.commit()
      print("Time:%s, Tag:%s" % (timestamp,tagid))

      # if you want to make this script trigger something on log in, this would be a
      # good place to insert that code

      time.sleep(.5)
      port.open()

    lastid = tagid
      

except KeyboardInterrupt:
  port.close()
  db.commit()
  db.close()
  print ("Program interrupted")

Last update: 11/01/2016